The primary objective of this study is to assess perianal and perirectal fistula healing (complete closure) based on endoscopic ultrasound (EUS) evaluation at 3 months and by PDAI (Pouchitis Disease Activity Index) and Fistula Drainage assessment by 6 months, showing no fistula (new or recurrence) in treatment of Crohn's' disease patient with Certolizumab (Cimzia).